Process of making molded articles.



UNITED STATES PATENT OFFICE.

TREVOR M. CAVEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KIE$ELGUHR COMPANY OFAMERICA, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA.

PROCESS OF MAKING MOLDED ARTICLES.

No Drawing.

To all whom it may concern.

Be it known that I, TREVOR M. CAVEN, a citizen of the United States,residing at Chicago, in'the county of Cook and State of Illinois, haveinvented a new and useful Process of Making Molded Articles, of whichthe following is a specification.

This invention relates to the manufacture of molded articles in whichkieselguhr or diatomaceous earth is the essential or main constituent,and the main object of the invention is to enable the materialconsisting of kieselguhr, with or without admixture of other substances,to be brought to a condition of proper fluidity or plasticity to enableit to be molded or cast.

I have found that when kieselguhr is mixed with suflicient water toproduce a stiff or slightly plastic mass, and this mass is then agitatedor broken up in a suitable mixer, the mixture loses its stiffness andbecomes relatively fluid. The increase in fluidity or breaking down ofthe kieselguhr, resulting from the amount of mixing or st1rring which isnecessary to produce a satisfactory mixture, is so great that the massis either too stiff to work at first, or too fluid and slippery formolding when the mixture is completed. I avoid this difficulty by addingsolid material to the mass in stages during the mixing operation, suchsolid material bein either additional kieselguhr or suitable ller, orother solid material.

My invention is especially adapted for the production of a material forlight porous molded articles, by admixture of organic material with thekieselguhr, this organic material being subsequently burned out; as theaddition of the organic material in stages enables me to increase theamount of organic material used and to correspondingly increase theporosity of the product.

The process is carried out as follows: The kieselguhr which may be theair-dried kieselguhr of commerce, is crushed to a suitable state ofdivision, for example, to a condition approximating that of coarse sand,and is then mixed with organic material, preferably cellulose or wood orvegetable fiber, such as sawdust, in suitable proportion,

either before or after the breaking down op eration.

A proportion suitable for producing a brick of minimum weight is asfollows: kieselguhr, 50%, sawdust 50%. There is Specification of LettersPatent.

Patented May 18, 1915.

Application filed April 1, 1914. Serial H0. 828,875.

some difficulty in introducing such a large proportion of sawdust intoeffective mixture w th the kieselguhr. In order to effect the mixture Iprefer to proceed as follows: kieselguhr is mixed With a portion of thesawdust, say 20% and sufficient water to form a moist plastic masscapable of retainmg its form but not enough water to cause 1t to becomefluid, and the material is then m xed in a suitable mixing apparatus them xing operation being carried on until the mixture is broken down, thatis to say, becomes relatively fluid. A further quantity of sawdust isthen added and the mixing operation continued, until the mixture againbreaks down and this being repeated, until the desired quantity ofsawdust has been incorporated into the mixture. If it is attempted toincorporate the entire quantity of sawdust with the kieselguhr and waterat one mixture, it is found that in order to make the mixture workablein the mixing apparatus, so much Watenmust be added that eventually whenthe mixing operation has been carried to a further point, the increaseof fluidity due to the breaking down of the mixture produces a sloppymass unfitted for molding. To produce a composition adapted for molding,it IS desirable that the mixture should contain no more water than isnecessary to produce plasticity of the composition and this effect issecured by adding the sawdust in stages so as to eliminate the effect ofthe mixing operation in breaking down, or rendering fluid the mixture.The mixture formed as above described is molded into the desired or reuired form for blocks, bricks or other articles, and the said articlesare dried in any suitable manner, for example, airdried, and are thenintroduced into any suitable kiln or furnace and subjected to suflicientheat to incinerate and decompose the sawdust. This heating operation ispreferably carried sufficiently far to practically burn terial, the mainobject and advantage of no this material being, however, that when it isburned away it leaves open spaces or porosities in the article,correspondingly reducing the density or weight of the article. In somecases the heating of the article may be carried on under such conditionsand for such length of time as to only partially drive ofl? the organicmatter, leaving, for example, a portion of the carbon content thereof asa binder for the article. Instead of the proportions above specified,any other suitable proportions may be used according to the porositydesired in the finished article, this porosity decreasing as theproportion of sawdust is decreased.

By the above described process I produce a molded article composed ofkieselguhr with a binder of vegetable ash supplementing the bindingeffect due to the action of the heat on the kieselguhr itself. A brickmay be made in this manner whose weight is only a small fraction of anordinary clay and sand brick of the same size. For example, by usingequal parts, as stated, of kieselguhr and sawdust a composition isobtained whose density as a whole is abouttWenty-five per cent of thatof ordinary brick.

In case a more compact material is required, I may use kieselguhr alone,it being first mixed with sufficient water to form a" still mass capableof being broken up by the mixed and when it has become broken down so asto be relatively fluid, more finely divided kieselguhr is added to makeit relatively stiff, and the breaking down action is repeated, theoperation being repeated until the thoroughly mixed product has theproper consistency for molding. Any solid material, such as a suitablefiller, for example sand, may be incorporated with the kieselguhr inthis manner. Moreover any suitable binder, such as lime, cement, oralkalis, capable of reacting with the kieselguhr may be added to thekieselguhr before or during the mixing operation. When the material isthoroughly mixed it is molded to shape and then treated by steam, fireheat or otherwise to render the mass coherent.

What I claim is:

1. The process of making a material for molded articles which consistsin mixing diatomaceous material with suflicient water to form a slightlyplastic mass, then subjecting the mixture to mechanical agitation untilit is broken down and assumes a state of increased fluidity, then addingmore solid material to reduce the fluidity, reagitating to againincrease the fluidity and repeating the addition of solid material andagitation until the requisite uniform mixture together with properfluidity for molding is attained.

2. The process of making molded articles which consists in mixin dividedkieselguhr with divided vegetable brous material and suflicient water toform a plastic mass, subjecting the mixture to mechanical agitationuntil the mixture is broken down and assumes a state of increasedfluidity, then adding a further uantity of divided-vegetable fibrousmateria and repeating the agitating action, continuing this successiveaddition of vegetable fibrous material until the required proportion ofsuch material is obtained, in suitable condition for molding thenmolding the resulting composition, drying the same, and then subjectingthe molded composition to the action of suflicient heat to decompose thevegetable fibrous material.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois,this 17 day of March, 1914.

Jos. FINN, W. HARDING.

It is hereby certified that in Letters Patent No. 1,139,637, granted May18, 1915, upon the application of Trevor M. Ceven, of Chicago, Illinois,for an improvement in Processes of Making Molded Articles," on errorappears in the printed specification requiring correctionas follows:Page 2, line 33, for the word "mixed read mixer; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office. n Y

Signed and sealed this 28th day of September, A. DJ, 1915.

[SEAL] J. T. NEWTON,

Acting Commissioner of Patents.

